(2S)-2,6-bis((((tert-butoxy)carbonyl)amino))hexanoic acid → (3aR,4S,7aR)-4-((S)-2,6-bis-tert-butoxycarbonylamino-hexanoyloxy)-4-m-tolylethynyl-octahydro-indole-1-carboxylic acid methyl ester

Participants

Reaction Steps

Synthesis in analogy to the General Method 1 starting from (3aS,4R,7aS)-4-hydroxy-4-m-tolylethynyl-octahydro-indole-1-carboxylic acid methyl ester and (S)-2,6-bis-tert-butoxycarbonylamino-hexanoic acid to yield (3aR,4S,7aR)-4-((S)-2,6-bis-tert-butoxycarbonylamino-hexanoyloxy)-4-m-tolylethynyl-octahydro-indole-1-carboxylic acid methyl ester. This NBoc-protected product was then stirred in hydrochloric acid dioxane solution (4M, 10 equiv.) at room temperature for 6 hrs. Subsequently the solvent was removed the residue dissolved in dichloromethane and washed with saturated sodium hydrogencarbonate solution. The organic layer was tried with sodium sulfate, filtrated and evaporated. The crude product was subjected to silica gel flash chromatography (ISCO CombiFlash; dichloromethane/methanol; 100/0 to 95/5) to yield (3aR,4S,7aR)-methyl 4-((S)-2,6-diaminohexanoyloxy)-4-(m-tolylethynyl)octahydro-1H-indole-1-carboxylate. MS [M+H] 442; RT=3.992 min; LCMS Method III

Provenance & Evidence